<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script>
        let recorder
        function start() {
            let videoTarget = document.getElementById('audio');
            navigator.mediaDevices.getUserMedia({audio: true, video: {width: 400, height: 600}})
                .then((stream) => {
                    recorder = new MediaRecorder(stream);
                    videoTarget.srcObject = stream;
                    videoTarget = (...arg) => {
                        console.log(arg);
                    }
                    recorder.ondataavailable = (event) => {
                        let url = URL.createObjectURL(event.data);
                        let link = document.createElement("a");
                        link.target = "_blank";
                        link.href = url;
                        link.click();

                    }
                    recorder.start();
                });
        }

        function stop() {
            recorder.stop();
        }
    </script>
</head>

<body>
<video id="audio" width="400" height="600" controls autoplay></video>
<input onclick="start()" type="button" value="开始" />
<input onclick="stop()" type="button" value="结束" />
</body>

</html>
